There are many fluid flow devices wherein fluid passes from a passage having a first cross sectional flow area into a passage of a larger cross sectional flow area and fluid is then required to flow through a further passage of reduced cross sectional flow area or to be ejected through a nozzle. Such changes in flow area often result in unwanted frictional pressure loss. Moreover, in many instances, the fluid conveying device or apparatus is arranged such that fluid will flow from a first passage into a second passage of larger cross sectional flow area and length and wherein the flow streamlines are interrupted and turbulence is generated which also results in friction pressure drop energy losses. Such energy losses may be undesirable in many fluid flow conveying devices and thus there has been a long felt need to minimize such losses.
There are several applications of fluid conveying devices wherein the above-mentioned pressure and energy losses are desired to be minimized. One application is in fluid mixing devices wherein two liquids are to be mixed, one liquid and one gas are to be mixed, two gasses are to be mixed, or a liquid or a gas is to be mixed with particulate solids for various purposes including a resultant chemical reaction or mechanical application of the fluids, such as preparation of cement mixtures, mixing drilling and fracturing fluids for well operations, spray painting and spray application of polymer coatings and similar materials. Still further, it is often desirable to provide mixing of liquids or gasses with fine particulate solids such as in mechanical abrasion applications or to merely disperse the solids in the fluid flow stream without reducing the flow stream energy.
Yet another application of fluid conveying devices wherein it is desirable to minimize fluid flow energy losses is in pulsed flow generation wherein fluid is used as a jet blast medium and the momentary interruption of fluid flow from a nozzle or the like is advantageous in the operation of the device such as in article cleaning applications and operations to otherwise remove material from a surface. Still further, in operations such as earth drilling or the use of high pressure jet penetrating devices, it is desirable to minimize energy loss in the fluid such as frictional pressure drops through the fluid conveying structure before the fluid is ejected therefrom. The present invention is directed to the above-mentioned ends as well as other objectives discussed herein.